Step 15: Acknowledgements and notes

Step 3: Designing a template

I just sketched a template for the panel out on paper to start with. You can arrange things however you like on the board, depending on the size of the case you are putting everything in. I designed everything on a 8.5"x11" piece of paper and just centered it on the wood panel (12"x12") when it was time to start cutting.

Start with arranging the speaker terminals, which I put on top in two rows of three. They have an outside dimension of 2-3/4" x 15/16".

Next came the toggle switch, key switch, and fuse holder. I centered the toggle switch horizontally on the board right under the speaker terminals. The key switch is to the right of the toggle switch, and the fuse holder is to the right of the key switch.

Underneath these main switches are the pushbutton switches and LED status indicators.The buttons I arranged in 4 columns of 3 buttons. Each button also has two LEDs; one on either side. I did not include the LEDs on the template, because I just eyeballed where to put them. You also might want to arrange them differently on yours, by putting the LED pairs under the switch or above them instead of on opposite sides.

Attached is a PDF template so you can print it out yourself. Print it and tape it over the panel you choose to use, and you can drill/saw through it to get everything properly lined up if you want to match my layout.

Lots to read, so sorry if this has been said...<br/><br/>To figure out the fuse value the easy way, build a regular ignitor, and then put an ammeter (multimeter) in the circuit. Battery - - - (Meter) - - - Ignitor. Obviuosly you need to wire the return to negative, but the diagram shows to wire in series.<br/><br/>If the amps needed to make the nichrome (or steel wool) is say, 3 amps, you use a 3.5A fuse. Depends on what you can get.<br/><br/>I don't know why you would use a fuse here...? As long as your wiring and all parts are rated for higher amps (I reckon your wire is probably rated at about 10A).<br/><br/>Worst that can happen is you get a fire at the wool end... That's what you want anyway =)<br/>

Oh, and this is a great instructable!

Thank you!

That would be fine as long as you don't try to shoot more than one cue at a time or you would have to determine the maximum number of cues you want to fire at a time. <br> <br>IMHO you are not talking massive circuitry here, and since the purpose is to blow things up, I wouldn't even worry about fusing it. The most that is going to happen is to inadvertently launch more cues than intended, which is just going to make it a better show anyway, so why bother. If there were an electronic timing circuit, then I could see doing that, or if there was an on-board battery charger that could overheat and short out, but besides that I wouldn't worry about it.

Okay, thank you, this is simpler than I had anticipated! As soon as I replace my broken multimeter I'll get to it.
And, you're right. After building this I realized that there was no reason to have the fuse in the circuit considering it's only 12v and not too much power. Next time I won't complicate things. I had planned to just take it off of the parts list and instructions, but figured that that would confuse people when they saw it in the pictures.

What's the price? i want to do this project but i am on a pretty tight budget. i would also be willing to downsize on the number of channels.

I believe that list ran about $135. If I had planned ahead I would have ordered the stuff direct from East Asia for a third of the cost but I didn't stumble across this until a couple days ago. If you use FourSquare on your phone you can get 20% off of your purchase with your first check-in.

wich ohm gets linked to led does it matter 470 0r 220

I'm pretty sure it doesn't matter but I hooked the 470's to the LEDs. Resistors can be linked in series in any order. The total resistance of each series is just the sum of each resistor.

Hi I love Radio Shack but the employees at our local store are not nearly as technology inclined as you are. Could you transfer to the Katy, TX store plz.

Haha well tell them they better get on point...our headquarters are in Texas!

Can i use dollar store foam board instead of plywood

A great cable would be irrigation wire for sprinklers it has a ton of conductors

<p>Same thought here, or even thermostat wire. 18G wire for long runs and all the wires are color coded for easy identification. :-)</p>

Great instructable! Im going to give this a shot.<br><br>Changes i would make are: 1)put the &quot;test&quot; lights where i could see them during hook up. It would prevent a lot of back and forth, and 2)put the key switch behind the toggle insted of in front of it (only key the &quot;arm&quot; circuit). That way you dont have to worry about someone switching it to arm while you are fixing a connection and setting something off.

If I want to use nichrome wire rated for 1.64ohms per foot what size resistor should I use?

If I have nichrome wire rated at 1.64ohms per foot what size resistor would I need?

I don't want to use those buttons to make it, what on-off toggle switches are an acceptable substitute as well as what would I need to do different to make it 10 firing switches? Thanks in advance

<p>Thanks a Ton, I have been trying to make one (more like just designing) for quite a while now.</p>

<p>how many watt do the resistors have to be?</p>

So, I finally built my controller! It is a 20 channel version. I wired everything up correctly, but the leds don't light up at all. I tested the connections a little with a multimeter, and there is no current flowing in between the leds... What could I do?

Hello! Why is it that my leds glow very dimly with 2 or even 1 470k resistors? Please reply rapidly! Thank you!

r u using a 12v battery??

I'm setting mine up to use RJ45 connectors to Rail-8 units from Pyrosure. I'm using bi-colour LEDs. Can anyone tell me if this schematic will work? <br> <br>Thanks

It looks great, might have a go with that myself if you dont mind haha

Hi, I am using 30m of Speaker (13 strand) wire from the control board to the fireworks and when i ignite them the firework goes off but the Red LED only fades it doesnt go off, so can i use a bigger battery to push more power to fully burn the ignitor or will it blow all the LED's??? PLEAS HELP THANK YOU!

Hi, I am running 30m of speaker (13 strand) wire and when i ignite a firework it lights and gets fired but the LED stays on why is this? Could i use a bigger battery to push the power further down the wire or will this Blow the LED's?????? PLEASE HELP THANK YOU

This will go great with my homemade fireworks. I've been learning how to make fireworks from this cool resource: <a href="http://howtomakefireworks.org" rel="nofollow">howtomakefireworks.org</a>. How expensive do you think it is to gather all the parts I need ?

Hi, I'm building a 24 channel version with my son. You've probably solved the fuse issue by now seeing as this is a couple years old but here's my take. <br> <br>Ohm's law (Voltage=Current x Resistance) dictates running 12V through your 940 Ohm resistors produces a current just shy 13 mA, enough to light your LED but not ignite the steel wool. (I read an FAA article somewhere that says the lowest amperage to ignite steel wool is 45 mA...). That's good for your test circuits and such, just what you want. <br> <br>Running the same 12V through the circuit without a resistor (when you fire for example) puts extremely high current through it since the resistance is only that inherent in the wiring (which in theory is supposed to be next to nothing). This would explain blowing the fuses given your set up. Yes, in theory the circuit should break when the match ignites and the steel wool gets ignited dropping the current to zero for that channel, but IF for some reason it doesn't (who knows what? stranger things have happened...) the heat build up in the wiring could have some serious effects (i.e. blow up the battery potentially). Putting a 1.5 Ohm resistor (say between the fuse and key switch) would drop your current to 8A and allow you to use a 10A fuse and still produce enough current to ignite the steel wool. <br> <br>If I've misstated something, someone please chime in and let me know.

If you need a battery charger this one should work: <br> <br>http://www.monstercells.com/leadacidsmartcharger08afor12vleadacidbatterywith3stagesfloating.aspx <br>

how do you charge the battery

two things: I'd just use a 1k ohm resistor. Why waste time and money using 2 instead? <br> <br>second, it is only 12v, but you are using a fair amount of current. an SLA battery can provide 10+ amps. Definitely worth having a fuse. I used some SLA batteries (a bit bigger than you use here) that were rated for 80ish amps output.

The test setting sends a low voltage current through the circuit to check continuity without supplying enough voltage to ignite the electric match.

Thanks sooo much im 13 years old and i manged to make this with ease thanks to you ill upload some photos of it later if I can. <br>Thanks again, <br>Charlie

Just looked at this and thinking of making my own, I saw you used two 470 Ohm resistors on the LEDs though, the Lite-on spec pages call out 2.6V and 30mA max, which would be a 330 Ohm max resistor. Was your LED circuit setting off your charges or was this just a mistake in the calcs?

Right, I decided to not run the LEDs at max output all of the time, so made the calculations based on them running at 20mA. Also, just to be safe and reduce the chance of there being enough power running through the ignitor. It was just a precautionary measure, and I do not know whether using 300 Ohm resistors would set off the charge or not.

Why did you decide to use two 470 Ohm resistors in series on each side and not just a single 940 Ohm resistor? (or one close by to that value)

say it if i'm wrong but if you flick the arm switch there goes a current through the igniter? <br>Does this current ignite it?

Will standard (Estes) model rocket igniters light the fireworks?

In picture no.6 what is the thing from radio-shack on the top left? is it a pair of wire cutters?

Not sure... I got one in my soldering kit but have no idea what it is.

I just made this by following your instructable this afternoon and was so disappointed when I got done. I was tired and my neck hurt from looking down soldering, so when i found that it didn't work, i was sad. I was just about to go to bed and try again tomorrow when i realized that i didn't put any test leads in the speaker terminals... turns out it works! awesome instructable! Thanks so much!

Cool! You should enter the R/C Contest!

can you send me a list of all the parts and where you get them <br>

I bought all the parts I needed on ebay. I've got around $100 in leds, switches, battery holders, ribbon cable, and everything else. I also set mine up where the test feature will only use 3v. to check it and will use 12v. when it is going to activate the cues.

Try Radio Shack....... also http://www.alliedelec.com/ is a good place to try but if you don't live in the United States idk where to send you

&nbsp;How do you make the actual igniter? and how do you attach it to the electric igniter?